Camera for color photography.



R. BERTHON & M. AUDIBERT.

CAMERA FOR COLOR PHOTOGRAPHY.

LL'PLHHHION FILED OO'1'.28,1911.

1,126,689. PatentedFehZ, 1915.

Zwenhzw IGWW/ KWnJ-AL/ WWW R. BBRTHON & M. AUDIBERT.

CAMERA FOR COLOR PHOTOGRAPHY.

APPLICATION FILED 00128, 1911.

Patented Feb. 2, 1915.

4 SHEETS-SHEET 2.

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R. BEBTHON & M. AUDIBERT.

CAMERA FOR COLOR PHOTOGRAPHY.

APPLICATION FILED OOT.Z8, 1911.

1912696895 Iatefited Feb. 2, 1915.

4 SHEETS-SHEET 3.

Wizwmes: Jim/@1150 12$:

n grmm/ w/ R. BERTHON & M. AUDIBEET.

CAMERA FOR COLOR PHOTOGRAPHY.

APPLICATION FILED 00128, 1911.

1,126,689. Patented Feb. 2, 1915.

4 SHEETS-SHEET 4.

FIG-

UNITED STATES PATENT OFFICE.

RODOLPHE BIITHON um IAUBICE AUDIBER'I', 0F VILLEUBIBANNE, FRANCE; SAIDBEBTHON ASSIGNOB 1'0 SAID AUDIBER'I'.

CAMERA FOB COLOR PHOTOGRAPHY.

lpecincation of Letters Patent.

Patented Feb. 2, 1915.

To all whom it may concern:

Be it known that we, RODOLPHE BERTHON and MAURICE AUDIBERT, bothcitizens of the Republic of France, residing at 7 Avenue Victor Hugo,Villeurbanne, in the Republic of France, have invented certain new anduseful Improvements in Cameras for Color Photography, of which thefollowing is a specification.

The present invention has for its ob ect to obtain, upon one and thesame surface, monochrome proofs arranged in juxtaposition and printed inthe fundamental colors which when projected onto a screen reproduce theobject photographed in colors.

With this object the invention consists in photographing instead of thescene itself a real or virtual image in space of this scene, by means ofan objective provided with prisms or mirrors which are arrangedconcentrically or uniformly in accordance with an axis of symmetry.Owing to the possibility of modifying the position of this image inspace as desired bydisplacing the optical element which produces it (anobjective of very wide aperture or a well-corrected divergent lens) itis possible, without the necessity for touching the system of prisms ormirrors, to modify as desired the position of the principal objectiveand consequently to regulate exactly the angular displacement of thethree monochromes upon the sensitized film (this displacement isproportionate to that of the objective) while at the same time insuringperfect focusing. The exact superposition of the three monochromes cantherefore also always be insured even when the apparatus for taking thepictures is not identical with the projection apparatus. On the otherhand, the distance of the image in space from the principal objectivebeing necessarily small and its relative dimensions being as small asdesired (proportionately to the focus of the optical element employed)it is always possible to utilize a principal objective of relativelylong focus and to give it a considerable aperture, thus reducing to theminimum the angle of deviation of the three monochromes and consequentlythe aberrations that the employment of prisms of considerable angles orvery oblique mirrors always entails. Finally, by imparting to the prismsor mirrors of the principal objective the form of'elements concentricwith the axis of this objective itself, or by arranging the refringentelements in accordance with an axis of symmetry, any stereoscopic effectbetween the three monochromes is eliminated. The projection cantherefore be effected on any desired scale without any danger ofproducing color smudges upon objects located in different planes. Thisadvantage is especially important in cinematographic projection wherethe enlargement is considerable. It should be noted also that the factof photographing not the object itself but an image of this object inspace, of itself contributes to eliminate the stereoscopic effectbetween the monochromes-the optical element which gives rise to theobject photographed in space reducing the relief of the several'planesin a large measure. Various methods of carrying the invention intopractice are illustrated by way of example in the accompanying drawings.

Figures 1, 1 and 1 are diagrammatic views of an apparatus for takingviews, the front objective of which is constituted by convergent lensesgiving a real and inverted image between the said objective and theprincipal objective, this image beingthen again taken by this latter andprojected upon the sensitized coat in three monochromes by means of adivergent prism apparatus. Figs. 2, 2 and 2 are similar views of anapparatus for taking views in which the front objective is constitutedby divergent lenses giving, in front of the said objective, a virtualimage which is then taken again and divided into three monochromes andprojected upon the sensitized coat through a colored screen. Fig. 3represents a modification in which the real or virtual image obtained bythe foregoing means is reflected and divided into three monochromes injuxtaposition by a system of mirrors. Figs. 4 and 5 represent to anenlarged scale, in front elevation and in section on the line 55respectively, the concentric prism arrangement serving for obtainingthree monochrome images upon the sensitized coat. Fig. 6 represents amodification in which the concentric prism arrangement is replaced byanother in which of this device of lenticular prisms to the view-takingapparatus. Figs. 10 and 11 represent respectively a section on the line10'10 and in plan a lens serving for obtaining an element of thelenticular prismatic device. Figs. 12 and 13 represent respectively insection on the line 12-12 and in plan, the outer concentric ring of thelenticular prismatic device cut from the said lens. Figs. 14 and 15represent respectively in section on the line 14--14 and in plan theeccentric median ring of the same lenticular prismatic device. Figs. 16and 17 represent in section on the line 16-16 and in plan respectivelythe central core of the same eccentricity as the foregoing of this samelenticular prismatic device. Figs. 18 and 19 represent respectively insection on the line 1818 and in plan the complete lenticular prismaticdevice obtained by the com bination of the three elements represented inFigs. 10 to 17.

In the embodiment of the invention illustrated on Figs. 1 to 2, A, Aindicate the principal ob ective provided at its optical center withconcentric prisms a, a and (1*. The central prism is designated a; a isan annular prism the inclination of which is exactly' inverse to that ofthe central prism a, while a is a glass ring having parallel facespermitting of the normal operation with deviation of the peripheral zoneof the objective. These elements as a whole are stuck to a glass ahaving parallel faces.

In the embodiment of the invention shown in Fig. 1 the prisms arearranged at the center of the objective A, A and are sufiiciently closefor the three zones of rays to be comprised in the pencil coming fromeach point of the image photographed and traversing the objective.

In front of the objective is another objective B having, in this case,convergent lenses 6. This objective is intendedto give a real image ofthe object D in space at C. There should be a suflicient aperture forthe image 0 viewed from the objective A to be entirely comprised in theluminous zone proceeding from the objective A to the objective B asbase. Strictly speaking the objective B could be dispensed with but theresult obtained would not be so good as when such an objective isemployed.

E designates the sensitized coating upon which the three juxtaposedimages 0, c, 0 are formed. This sensitized coating may be on a plate,cut film or cinematographic film displaced by any convenient knownmeans. In front of this sensitized coatinga threecolor screen F of thefundamental colors is arranged, the red portion being designated by f,the green portion by f and the blue I aaaaeee ortion by F. Thisthree-color screen could e dispensed with if the prisms a, a and a werecolored with the same colors as the screen.

The adjustment of the position of the objectives A A and B relatively tothe sensi: tized plate on the one hand and to the object on the otherhand, is obtained by means of a known system of screws and racks whichis not illustrated in the drawings.

The objective A A is carried by a single tube G capable'of rotatingthrough a certain angle aroundits axis with the object of permitting ofdirecting the prisms relatively to the images without having to touchthe prisms themselves. The relative displacement of the images and thedirection of the prisms are therefore regulated without touchin ment 0which is established once for all with perfect precision.

If desired the prisms a, a, a ma be arranged in front of the objectivesA as illustrated in Fig. 1. The prisms a, a, a may also be arrangedbehind the objective A A as illustrated in Fig. 1". In the modificationsshown in Figs. 1 and 1 the prisms a, a, a should be arrangedsufiiciently close to the objective A A for the three zones of rays tobe comprised in the pencil coming from each point of the imagephotographed and traversing the objective. In these fi ures the screen Fand the front objective I3 have been omitted, the lens tube beingconsequently shown broken.

Another modification is illustrated in Fig. 2 where the front objectiveB is provided with divergent lenses 6'. In this case the objective B isintended to give a virtual image of the object D in space at C. Theobjective A A and the prisms a, a a are similar to those employed inFig. 1. The coating E and the screen F are also similar to thoseemployed in Fig. 1.

In front of the sensitlzed coating and almost in contact therewith theremay be arranged prisms H with inclinations h, 71. inverse to those whichhave given rise to the corresponding images. A simple glass h withparallel faces and of such thickness that the reflected image presentsthe maximum of sharpness is placed opposite the image produced withoutdeflection. The

the latter, the relative arrangeprism and the glass can be cut in asingle of the image photographed and transversing the objective. For thesake of clearness the objective B has been omitted from these A furthermodification is shown in Fig. 3 the prisms being replaced by inclinedmirrors m, m m, the mirror 112. being inclined at 45 to the axis of theapparatus, m rather more, and m rather less. The sensitized coat E wouldthen be parallel with the axis of the front objective.

The concentric prism arrangement is clearly illustrated in Figs. 4 and5.

For projection the arrangement of prisms represented in Figs. 1 to 2, 4and 5 may be employed.

The concentric prism arrangement which has just been describedcorresponds to a center of a single pupil, but any arrangement of prismsthe refringent elements of whichare arranged in accordance with a centerof symmetry would lead to the same result.

Figs. 6 to 8 represent a device of this kind which is constituted by twoprisms L and N of the same angle stuck one to the other in such a manneras to compensate each other exactly, the prisms being arranged in theobjective itself. The prism L is provided with apertures Z, l, 1 and theprism N with apertures 11., n, 01. The apertures in the prism L do notregister with the apertures in the prism N. In the points at which thetwo prisms are superposed the rays pass through directly; at the pointsopposite the apertures in one of the prisms, on the other hand the otherprism deviates the rays which strike it. In order to obtain the desiredresult it is therefore suflicient that the apertures formed in theprisms L and N should have a common center of symmetry which is the casewhen these apertures present the same form, the same dimensions andoccupy the apexes of a regular polygon. Such prisms should beachromatized and the defects of aberration of prisms with entirely planesurfaces should be corrected. This correction may be obtained by applyinalmost in contact with the photographic p ate or film, prisms, J and Kwhich present slight curvature and of the same angle as the risms L andN but inversely directed. hese prisms mi ht be replaced by reflectingsurfaces wit single center of symmetry serving the same purpose as themirrors in Fig. 3.

The foregoing description sets forth the essential principle of theinvention and the means for carrying it into practice. The employment ofprisms with absolutely plane faces however resents the inconvenience ofproducing de ects of optical aberration which is remedied by giving thema slight curvature. A very simple method of obtaining SllCh prismsconsists in cutting them from three ordinary photographic lenses,well-corrected and as thin as ossible, as shown in Figs. 9 to 19. Theollowin is the method adopted with this object. l aking three lenses 0similar tothat represented in Figs. 10 and 11 in the accompanyingdrawing, from the first there is cut a ring 71 eccentric to the axis ofthe lens (Figs. 14 and 15) from the third a core 2? (Figs. 16 and 17)also eccentric to the axis of the lens, but of such size as to fit intothe ring z"; and from the second, a ring 5 is cut concentric with theaxis of the lens and into which the ring a" is adapted to fit. Theseseveral elements are then assembled in the manner represented in Figs.18

and 19.

If the lenses employed are convergent, they furnish a system of prismswhich are utilizable alone, as is the case in Fig. 9, which shows theprisms a, i, 2', cut and assembled as above described, used incombination with an apparatus similar in construction to that shown inFig. 6.

What we claim and desire to secure by Letters Patent of the UnitedStates is 1. A photographic apparatus for obtainin monochrome juxtaposedproofs comprlsing in combination an objective for p rojecting an image,and a device compris ng concentric prisms for changing the d1rect1on ofthe rays and projecting the image onto a sensitized surface.

2. A photographic apparatus for obta ning monochrome juxtaposed proofscomprising in combination a front objective, a second objective and asystem of prlsms formed of juxtaposed elements for changing thedirection of the rays and pro ecting an image of the object onto asensitized coating.

3. A photographic apparatus for obtaining monochrome juxtaposed proofscomprising the combination with a front ob ectlve system of lenses forobtainin a virtual image of the object photograp ed, of anotherobjective a system of lenses and concentric prisms formed of astigmaticpr1smatic curved elements c11t;'-from photographic lenses for thepurpose of tal 1ng up the said image and breaking it mto monochromesprojected through a three color screen onto a sensitized surface.

In testimony whereof we aflix our signatures in presence of twowitnesses.

RODOLPHE BERTHON. MAURICE AUDIBERT.

Witnesses:

JEAN GERMAIN, GUILLAUME Procmz.

